Water Journal : Water Journal November 2012-1
46 NOVEMBER 2012 water feature articles special report The growth of Australia’s coal seam gas industry has been rapid in its speed and scope. Billions of dollars are pouring into regional parts of southern Queensland and northern New South Wales as global miners rush to exploit vast reserves of methane gas buried deep underground in coal seams. Thousands of wells are being sunk, hundreds of kilometres of pipes laid and liquefied natural gas (LNG) facilities built to feed a thriving export industry. But the boom times are also fuelling controversy. To release the methane, mining companies have to sink wells deep underground and depressurise the coal beds. This involves removing huge amounts of groundwater, raising questions about potential impacts on the Great Artesian Basin (GAB) and connected aquifers. There are also issues surrounding the safe disposal of the water, which has varying levels of impurities. And for hard to reach gas, a technique called fracking is used – the hydraulic fracturing of coal seams by pumping water, sand and chemicals through wells at high pressure. Unlike previous Australian mining booms in remote outback areas, CSG is found under farmland and country towns. A protest movement has grown in regional communities worried about the potential impacts of these processes, including the shared use of limited groundwater and the risks of contamination. CSG mining companies disagree and are trying to allay their concerns through environmental impact statements and historical overseas information. The scientific community is urging caution. Hydrologists point to major gaps in our understanding of groundwater dynamics and chemistry of Australia’s artesian systems. They argue that we are still very much at the entry level of knowing how these complex sub-surface water bodies will be affected because of a paucity of fundamental data and baseline information. Current analyses are focused on individual mines or tenements and, therefore, much more is needed to assess cumulative impacts. Because little is known about how deeper systems interact with shallower systems, there are concerns about the potential long-term impacts of water removal on such a cumulative scale. Multi-Billion Dollar Investment One thing not in dispute is the economic benefits. Global mining companies have previously indicated they are investing more than $70 billion in CSG ventures over the next five years. The major focus is Queensland, where the number of wells drilled annually has increased from 10 in the early 1990s to nearly 600 in 2010–11. In little over a decade, annual CSG production has jumped from four petajoules* to 234 petajoules. The rate of extraction will continue to rise, with the Queensland Government predicting 25,000 to 35,000 wells will be drilled by mining companies in future decades. Gas from coal seams several hundred metres to kilometres deep now supplies about one-third of the gas used in eastern Australia and Asian exports of the processed LNG is surging. The amount of water being extracted from underground water systems is also increasing. Current modelling from mining companies suggests a total of 75,000ML a year will be removed from the Surat Basin section of the GAB, the focus of most of the mining activity. The draft Surat Underground Water Impact Report from the Queensland Water Commission (QWC) predicts a figure closer to 95,000ML a year. Removing groundwater on such a scale has the potential to affect both surface and groundwater systems, and risk land subsidence and cross-contamination between water bodies. Because aquifers that are depressurised can sometimes collapse to some degree, there is also a risk that the systems will never be fully restored to their previous condition for subsurface water storage. National Body Examines CSG Impacts These are all issues to be investigated by an Independent Expert Scientific Committee. An interim committee was established in January by Environment and Water Minister, Tony Burke, in a $200 million initiative to advise on CSG and large coal mining. Chaired by Professor Craig Simmons, Director of the National Centre for Groundwater Research and Training (NCGRT) in Adelaide, the interim committee will commission and fund water bioregional assessments in priority regions and oversee research into potential water-related impacts of mining. The funding also includes $50 million in incentive payments for the states to act on the committee’s advice when considering approvals. The governments of Queensland, New South Wales, South Australia and Victoria have already signed up to the National Partnership Agreement. “National coordination and guidance is extremely important because these basins cross state borders,” Professor Simmons said. “You can’t have one state regulating part of the GAB and other states doing something else and not agreeing – consistency is essential. The other thing that’s coming through very strongly is the need for good regulation and compliance with leading best practice frameworks and guidelines for mining operations.” (*One petajoule = 1,000,000 gigajoules) Coal Seam Gas Mining and Groundwater A review of the controversies around and potential impacts of CSG in Australia Land-drilling rig on a coal seam gas project in Queensland.
Water Journal December 2012
Water Journal September 2012-1